Set up a multi-cluster mesh outside Google Cloud
This guide explains how to set up a multi-cluster mesh for the following platforms:
- Google Distributed Cloud
- Google Distributed Cloud
- GKE on Azure
- GKE on AWS
- Attached clusters, including Amazon EKS clusters and Microsoft AKS clusters
This guide shows how to set up two clusters, but you can extend this process to incorporate any number of clusters into your mesh.
Before you begin
This guide assumes you installed Cloud Service Mesh using
asmcli install
. You need
asmcli
and the configuration package that asmcli
downloads to the
directory that you specified in --output_dir
when you ran asmcli install
.
If need to get set up, follow the steps in
Install dependent tools and validate cluster
to:
- Install required tools
- Download
asmcli
- Grant cluster admin permissions
- Validate your project and cluster
You need access to the kubeconfig files for all the clusters that you are setting up in the mesh.
Set up environment variables and placeholders
You need the following environment variables when you install the east-west gateway.
Create an environment variable for the project number. In the following command, replace FLEET_PROJECT_ID with the the project ID of the fleet host project.
export PROJECT_NUMBER=$(gcloud projects describe FLEET_PROJECT_ID \ --format="value(projectNumber)")
Create an environment variable for the mesh identifier.
export MESH_ID="proj-${PROJECT_NUMBER}"
Create environment variables for the cluster names in the format that
asmcli
requires.export CLUSTER_1="cn-FLEET_PROJECT_ID-global-CLUSTER_NAME_1" export CLUSTER_2="cn-FLEET_PROJECT_ID-global-CLUSTER_NAME_2"
Get the context name for the clusters by using the values under the
NAME
column in the output of this command:kubectl config get-contexts
Set the environment variables to the cluster context names, which this guide uses in many steps later:
export CTX_1=CLUSTER1_CONTEXT_NAME export CTX_2=CLUSTER2_CONTEXT_NAME
Install the east-west gateway
In the following commands:
Replace
CLUSTER_NAME_1
andCLUSTER_NAME_2
with the names of your clusters.Replace
PATH_TO_KUBECONFIG_1
andPATH_TO_KUBECONFIG_2
with the kubeconfig files for your clusters.
Anthos Clusters
Mesh CA or CA Service
Install a gateway in cluster1 that is dedicated to east-west traffic to
$CLUSTER_2
. By default, this gateway will be public on the Internet. Production systems might require additional access restrictions, for example firewall rules, to prevent external attacks.asm/istio/expansion/gen-eastwest-gateway.sh \ --mesh ${MESH_ID} \ --cluster ${CLUSTER_1} \ --network default \ --revision asm-1232-2 | \ ./istioctl --kubeconfig=PATH_TO_KUBECONFIG_1 \ install -y --set spec.values.global.pilotCertProvider=kubernetes -f -
Install a gateway in
$CLUSTER_2
that is dedicated to east-west traffic for$CLUSTER_1
.asm/istio/expansion/gen-eastwest-gateway.sh \ --mesh ${MESH_ID} \ --cluster ${CLUSTER_2} \ --network default \ --revision asm-1232-2 | \ ./istioctl --kubeconfig=PATH_TO_KUBECONFIG_2 \ install -y --set spec.values.global.pilotCertProvider=kubernetes -f -
Istio CA
Install a gateway in cluster1 that is dedicated to east-west traffic to
$CLUSTER_2
. By default, this gateway will be public on the Internet. Production systems might require additional access restrictions, for example firewall rules, to prevent external attacks.asm/istio/expansion/gen-eastwest-gateway.sh \ --mesh ${MESH_ID} \ --cluster ${CLUSTER_1} \ --network default \ --revision asm-1232-2 | \ ./istioctl --kubeconfig=PATH_TO_KUBECONFIG_1 \ install -y --set spec.values.global.pilotCertProvider=istiod -f -
Install a gateway in
$CLUSTER_2
that is dedicated to east-west traffic for$CLUSTER_1
.asm/istio/expansion/gen-eastwest-gateway.sh \ --mesh ${MESH_ID} \ --cluster ${CLUSTER_2} \ --network default \ --revision asm-1232-2 | \ ./istioctl --kubeconfig=PATH_TO_KUBECONFIG_2 \ install -y --set spec.values.global.pilotCertProvider=istiod -f -
Azure, AWS, & Attached
Mesh CA
Install a gateway in cluster1 that is dedicated to east-west traffic to
$CLUSTER_2
. By default, this gateway will be public on the Internet. Production systems might require additional access restrictions, for example firewall rules, to prevent external attacks.asm/istio/expansion/gen-eastwest-gateway.sh \ --mesh ${MESH_ID} \ --cluster ${CLUSTER_1} \ --network default \ --revision asm-1232-2 | \ ./istioctl --kubeconfig=PATH_TO_KUBECONFIG_1 \ install -y --set spec.values.global.pilotCertProvider=istiod -f -
Install a gateway in
$CLUSTER_2
that is dedicated to east-west traffic for$CLUSTER_1
.asm/istio/expansion/gen-eastwest-gateway.sh \ --mesh ${MESH_ID} \ --cluster ${CLUSTER_2} \ --network default \ --revision asm-1232-2 | \ ./istioctl --kubeconfig=PATH_TO_KUBECONFIG_2 \ install -y --set spec.values.global.pilotCertProvider=istiod -f -
Istio CA
Install a gateway in cluster1 that is dedicated to east-west traffic to
$CLUSTER_2
. By default, this gateway will be public on the Internet. Production systems might require additional access restrictions, for example firewall rules, to prevent external attacks.asm/istio/expansion/gen-eastwest-gateway.sh \ --mesh ${MESH_ID} \ --cluster ${CLUSTER_1} \ --network default \ --revision asm-1232-2 | \ ./istioctl --kubeconfig=PATH_TO_KUBECONFIG_1 \ install -y --set spec.values.global.pilotCertProvider=istiod -f -
Install a gateway in
$CLUSTER_2
that is dedicated to east-west traffic for$CLUSTER_1
.asm/istio/expansion/gen-eastwest-gateway.sh \ --mesh ${MESH_ID} \ --cluster ${CLUSTER_2} \ --network default \ --revision asm-1232-2 | \ ./istioctl --kubeconfig=PATH_TO_KUBECONFIG_2 \ install -y --set spec.values.global.pilotCertProvider=istiod -f -
Exposing services
Since the clusters are on separate networks, you need to expose all services
(*.local
) on the east-west gateway in both clusters. While this gateway is
public on the Internet, services behind it can only be accessed by services with
a trusted mTLS certificate and workload ID, just as if they were on the same
network.
Expose services via the east-west gateway for
CLUSTER_NAME_1
.kubectl --kubeconfig=PATH_TO_KUBECONFIG_1 apply -n istio-system -f \ asm/istio/expansion/expose-services.yaml
Expose services via the east-west gateway for
CLUSTER_NAME_2
.kubectl --kubeconfig=PATH_TO_KUBECONFIG_2 apply -n istio-system -f \ asm/istio/expansion/expose-services.yaml
Enable endpoint discovery
Run the asmcli create-mesh
command to enable endpoint discovery. This
example only shows two clusters, but you can run the command to enable
endpoint discovery on additional clusters, subject to the
GKE Hub service limit.
./asmcli create-mesh \
FLEET_PROJECT_ID \
PATH_TO_KUBECONFIG_1 \
PATH_TO_KUBECONFIG_2
Verify multicluster connectivity
This section explains how to deploy the sample HelloWorld
and Sleep
services
to your multi-cluster environment to verify that cross-cluster load
balancing works.
Enable sidecar injection
Locate the revision label value, which you use in later steps.
Use the following command to locate the revision label, which you will use in later steps.
kubectl -n istio-system get pods -l app=istiod --show-labels
The output looks similar to the following:
NAME READY STATUS RESTARTS AGE LABELS istiod-asm-173-3-5788d57586-bljj4 1/1 Running 0 23h app=istiod,istio.io/rev=asm-173-3,istio=istiod,pod-template-hash=5788d57586 istiod-asm-173-3-5788d57586-vsklm 1/1 Running 1 23h app=istiod,istio.io/rev=asm-173-3,istio=istiod,pod-template-hash=5788d57586
In the output, under the LABELS
column, note the value of the istiod
revision label, which follows the prefix istio.io/rev=
. In this example,
the value is asm-173-3
. Use the revision value in the steps in the next section.
Install the HelloWorld service
Create the sample namespace and the Service Definition in each cluster. In the following command, substitute REVISION with the
istiod
revision label that you noted from the previous step.for CTX in ${CTX_1} ${CTX_2} do kubectl create --context=${CTX} namespace sample kubectl label --context=${CTX} namespace sample \ istio-injection- istio.io/rev=REVISION --overwrite done
where REVISION is the
istiod
revision label that you previously noted.The output is:
label "istio-injection" not found. namespace/sample labeled
You can safely ignore
label "istio-injection" not found.
Create the HelloWorld service in both clusters:
kubectl create --context=${CTX_1} \ -f ${SAMPLES_DIR}/samples/helloworld/helloworld.yaml \ -l service=helloworld -n sample
kubectl create --context=${CTX_2} \ -f ${SAMPLES_DIR}/samples/helloworld/helloworld.yaml \ -l service=helloworld -n sample
Deploy HelloWorld v1 and v2 to each cluster
Deploy
HelloWorld v1
toCLUSTER_1
andv2
toCLUSTER_2
, which helps later to verify cross-cluster load balancing:kubectl create --context=${CTX_1} \ -f ${SAMPLES_DIR}/samples/helloworld/helloworld.yaml \ -l version=v1 -n sample
kubectl create --context=${CTX_2} \ -f ${SAMPLES_DIR}/samples/helloworld/helloworld.yaml \ -l version=v2 -n sample
Confirm
HelloWorld v1
andv2
are running using the following commands. Verify that the output is similar to that shown.:kubectl get pod --context=${CTX_1} -n sample
NAME READY STATUS RESTARTS AGE helloworld-v1-86f77cd7bd-cpxhv 2/2 Running 0 40s
kubectl get pod --context=${CTX_2} -n sample
NAME READY STATUS RESTARTS AGE helloworld-v2-758dd55874-6x4t8 2/2 Running 0 40s
Deploy the Sleep service
Deploy the
Sleep
service to both clusters. This pod generates artificial network traffic for demonstration purposes:for CTX in ${CTX_1} ${CTX_2} do kubectl apply --context=${CTX} \ -f ${SAMPLES_DIR}/samples/sleep/sleep.yaml -n sample done
Wait for the
Sleep
service to start in each cluster. Verify that the output is similar to that shown:kubectl get pod --context=${CTX_1} -n sample -l app=sleep
NAME READY STATUS RESTARTS AGE sleep-754684654f-n6bzf 2/2 Running 0 5s
kubectl get pod --context=${CTX_2} -n sample -l app=sleep
NAME READY STATUS RESTARTS AGE sleep-754684654f-dzl9j 2/2 Running 0 5s
Verify cross-cluster load balancing
Call the HelloWorld
service several times and check the output to verify
alternating replies from v1 and v2:
Call the
HelloWorld
service:kubectl exec --context="${CTX_1}" -n sample -c sleep \ "$(kubectl get pod --context="${CTX_1}" -n sample -l \ app=sleep -o jsonpath='{.items[0].metadata.name}')" \ -- /bin/sh -c 'for i in $(seq 1 20); do curl -sS helloworld.sample:5000/hello; done'
The output is similar to that shown:
Hello version: v2, instance: helloworld-v2-758dd55874-6x4t8 Hello version: v1, instance: helloworld-v1-86f77cd7bd-cpxhv ...
Call the
HelloWorld
service again:kubectl exec --context="${CTX_2}" -n sample -c sleep \ "$(kubectl get pod --context="${CTX_2}" -n sample -l \ app=sleep -o jsonpath='{.items[0].metadata.name}')" \ -- /bin/sh -c 'for i in $(seq 1 20); do curl -sS helloworld.sample:5000/hello; done'
The output is similar to that shown:
Hello version: v2, instance: helloworld-v2-758dd55874-6x4t8 Hello version: v1, instance: helloworld-v1-86f77cd7bd-cpxhv ...
Congratulations, you've verified your load-balanced, multi-cluster Cloud Service Mesh!
Clean up
When you finish verifying load balancing, remove the HelloWorld
and Sleep
service from your cluster.
kubectl delete ns sample --context ${CTX_1} kubectl delete ns sample --context ${CTX_2}